Search Algorithms and Applications
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Fig. 2. Hexagon 3 new check points are formed and evaluated as new candidates to predict the motion vectors
3. Unrestricted Hexagon Diamond Search UHDS16 algorithm
This section starts with some modifications from the FUHS16 algorithm. In this section, the UHDS16 technique is introduced. This technique is developed to have unrestricted search.
To achieve this, a simple and efficient fast block-matching algorithm based on hexagon- diamond search shape is proposed. UHDS16 is designed uniquely with a large hexagon
shape and shrink diamond search step SDSS. Large hexagon is more unique to identify the motion vector in the small region of large hexagon shape. Finally, the shrink diamond
search step is to locate the best-matched motion vector in the large hexagon small region. Experimental results show that the proposed UHDS16 algorithm significantly produces
smaller computation complexity. The speed and accuracy of the rood pattern based search algorithm are highly related to the
size of the pattern. First step of the proposed method permits the algorithm to adapt itself to the content of motion. In most cases, adjacent blocks belong to the same moving object that
has similar motions. Therefore, it is reasonable to predict the motion of current blocks from motion vectors of adjacent blocks.
and UHDS8 Algorithms for Video Sequence
229 UHDS16 is designed to have repetitive search in the small region of large hexagon search
shape. The large hexagon search shape is to locate the best motion vector before switching to shrink diamond search step for the final best-matched motion vector coordinate.
The UHDS algorithms are implemented using two different block sizes. Initially, the UHDS16 algorithm is developed using the 16 × 16 block size with search windows 15 × 15 and then the
same technique and ideology is used for 8 × 8 block size with search windows size 7 × 7. The difference between UHDS16 algorithm and UHDS8 algorithm is the block size.
Figure 1 illustrates the extraction of 8 × 8 pixels block size from a single frame. The FUHS16 algorithm block extraction procedure is applied in the UHDS8 algorithm. This means, that
each frame will have 18 blocks horizontally and 22 blocks vertically.
4. Unrestricted Hexagon Diamond Search UHDS16 and UHDS8 algorithm search procedure
